Bearing race cooling

ABSTRACT

A cooling architecture can include a longitudinally extending radially inner shaft, a radially outer support, and a bearing assembly. The longitudinally extending radially inner shaft can include an inner race. The inner race can define an inner circumferential chamber configured to carry an inner working fluid. The radially outer support can include an outer race. The bearing assembly can include a plurality of roller bearings disposed radially between the inner race and the outer race. The bearing assembly can be configured to radially align the inner shaft with respect to the outer support.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/119,583, filed Aug. 31, 2018, first named inventor: BradleyD. Belcher; and is related to concurrently filed U.S. patent applicationSer. No. 16/135,884, entitled “Bearing Race Cooling in a Geared TurbofanEngine”, inventors: Bradley D. Belcher and Robert T. Duge. The entiretyof these aforementioned applications are herein incorporated byreference.

BACKGROUND Field of the Disclosure

The present disclosure relates to cooling for bearing assemblies.

Description of Related Art

Energy conversion devices (e.g., electrical generators, engines) oftenincorporate rotating shafts for mechanical power transmission. Rotatingshafts can be supported by inner structure (e.g., a rod extendingthrough a hollow rotating shaft) or outer structure (e.g., a collarsurrounding a circumference of a rotating shaft). Supporting structurecan be static or rotating.

Rotation of a shaft with respect to its support generates friction,which (a) wastes energy that would otherwise be transmitted by the shaftand (b) damages the shaft and/or the support. To reduce friction andenable smooth rotation, bearing assemblies can be disposed between arotating shaft and a support. Examples of bearing assemblies appear inU.S. Pub. No. 2018/0010525 to Madge, U.S. Pat. No. 8,662,756 to Care,and U.S. Pub. No. 2017/0082065 to Swift.

SUMMARY

A rolling bearing system can include a rotatable shaft defining an axisand a support member positioned radially outward of said shaft. Anannular inner race can be coupled to the shaft and an annular outer racecan be coupled to the support member and can be axially aligned with theinner race. A bearing assembly comprising a plurality of roller bearingscan be circumferentially spaced and radially disposed between the innerand outer races. One or more of the inner and outer races can define aninterior chamber bound at least in part by a circumferential bearingfacing wall. The bearing facing wall can define a plurality of outletpassages providing fluid communication between the interior chamber andthe exterior of the race.

A rolling bearing system can include a heat management system. The heatmanagement system can include a cooling fluid flowpath including in partone or more inlet passages, an interior chamber, and a plurality ofoutlet passages defined by an inner and/or an outer bearing race.

The outlet passages can be spaced axially along a bearing facing wall ofa race. The outlet passages can be spaced circumferentially around thebearing facing wall and can be circumferentially aligned with one ormore of the roller bearings. The outlet passages can be radially angledand/or radially tapered.

A method of heat management in a roller bearing system can includeflowing a cooling fluid into a chamber defined by the inner and/or outerrace of the roller bearing system, and ejecting the cooling fluid fromthe chamber at circumferential locations aligned with each rollerbearing. The cooling fluid can be pressurized to effect the formation ofa fluidic barrier between the races and the roller bearings.

BRIEF DESCRIPTION OF THE DRAWINGS

Various Figures use “L” for the longitudinal (also called “axial”)dimension, “R” for the radial dimension, and “C” for the circumferentialdimension. The claimed inventions are not limited to the depictedlongitudinal, radial, and circumferential orientations.

FIG. 1A is a cross-sectional schematic view of an exemplary gas turbineengine.

FIG. 1B is an enlarged cross-sectional schematic view of the exemplarygas turbine engine in FIG. 1A.

FIG. 2 is a cross-sectional schematic view of an exemplary hybridengine.

FIG. 3 is a cross-sectional schematic view of an exemplary first coolingarchitecture, which can be used in the engines shown in FIGS. 1A, 1B,and 2.

FIG. 4 is a cross-sectional schematic view of the exemplary firstcooling architecture.

FIG. 5 is a cross-sectional schematic view of the exemplary firstcooling architecture.

FIGS. 6A and 6B are cross-sectional schematic views of the exemplaryfirst cooling architecture.

FIGS. 7 and 8 are schematics of exemplary fluid circuits for the firstcooling architecture.

FIG. 9 is a cross-sectional schematic view of the exemplary secondcooling architecture.

FIG. 10 is a cross-sectional schematic view of the exemplary secondcooling architecture.

FIG. 11 is a cross-sectional schematic view of the exemplary secondcooling architecture.

FIG. 12 is a cross-sectional schematic view of the exemplary secondcooling architecture.

FIGS. 13 and 14 are schematics of exemplary fluid circuits for thesecond cooling architecture.

FIG. 15 is a cross-sectional schematic view of the exemplary secondcooling architecture.

FIG. 16 is a block diagram of an exemplary processing system.

FIG. 17 is a block diagram of an exemplary method of controlling thefirst cooling architecture.

DETAILED DESCRIPTION

Illustrative (i.e., example) embodiments are discussed below and shownin the figures. The claims are not limited to the illustrativeembodiments. Therefore, some implementations of the claims will havedifferent features than in the illustrative embodiments. Changes to theclaimed inventions can be made without departing from their spirit. Theclaims are intended to cover implementations with such changes.

At times, the present application uses directional terms (e.g., front,back, top, bottom, left, right, etc.) to give the reader context whenviewing the Figures. The claimed inventions are not limited to anyparticular direction or orientation. Any directional term can bereplaced with a numbered term (e.g., left can be replaced with first,right can be replaced with second, and so on). Any absolute term (e.g.,high, low, etc.) can be replaced with a corresponding relative term(e.g., higher, lower, etc.).

As shown in FIG. 2, a gas turbine engine 10 can be mechanically coupledwith an electric generator 200 via shaft 26. Gas turbine engine 10 caninclude a compressor 18 linked with a turbine 22 via a shaft 26. Acombustor 21 can be disposed intermediate compressor 18 and turbine 22.

Electric generator 200 can include a rotor 212 and a stator 214. One ofrotor 212 and stator 214 can include magnets and the other of rotor 212and stator 214 can act as an armature. During operation, turbine 22 candrive rotor 212 via shaft 26. The rotation of rotor 212 with respect tostator 214 can generate alternating electric current, which can besupplied via electrical lines 252 to one or more electrical consumptiondevices 254 (e.g., a battery and/or an electric motor coupled with afan).

As shown in FIG. 2, shaft 26 and/or rotor 212 can be rotationallycentered about principle axis PA by one or more bearing assemblies 233,which can be disposed within electric generator 200 and/or gas turbine10. Bearing assemblies 233 can be radially disposed between the rotatingcomponent (e.g., shaft 26 or rotor 212) and static structure (e.g.,engine casing 262, stator 214, or generator casing (not shown)).

FIGS. 1A and 1B show another embodiment of gas turbine engine 10, whichis structure as a turbofan (e.g., a geared turbofan). As shown in FIGS.1A and 1B, a fan 14 can be disposed in a fan casing 12. Fan 14 can drawair into gas turbine engine 10. Air drawn into gas turbine engine 10 canseparate between a bypass flow path 32 through fan casing 12 and a coreflow path 35 through compressors 16, 18, combustor 21, and turbines 22,24.

Combustor 21 can inject fuel into core air flow 34. Combustor 21 canignite the fuel/air mixture to produce high pressure combustionproducts. The high-pressure combustion products can flow past high speedturbine 22, causing high speed turbine 22 to spin. The lower pressurecombustion products exhausted from high speed turbine 22 can flow pastlow speed turbine 24, causing low speed turbine 24 to spin. Combustionproducts can leave gas turbine engine 10 via exhaust nozzle 36.

High speed turbine 22 and high speed compressor 18 can be mounted toopposing ends of high speed shaft 26. Low speed turbine 24 and low speedcompressor 16 can be mounted to opposing ends of low speed shaft 28.Therefore, high speed turbine 22 can drive high speed shaft 26 alongwith high speed compressor 18. Similarly, low speed turbine 24 can drivelow speed shaft 28 along with low speed compressor 16.

According to some embodiments (not shown), fan 14 is directly mounted tolow speed shaft 28 such that torque delivered by low speed turbine 24drives both fan 14 and low speed compressor 16 at a common speed.According to other embodiments, and as shown in FIGS. 1 and 2, a gearbox30 is disposed intermediate fan 14 and low speed shaft 28.

Gearbox 30 can perform a speed reduction function, enabling fan 14 torotate at a lesser speed than low speed compressor 16, which can improvethe fuel efficiency of gas turbine engine 10. Fan 14, gearbox 30, lowspeed compressor 16, high speed compressor 18, low speed turbine 22,high speed turbine 24, low speed shaft 28, and high speed shaft 26 canbe rotatable about engine principle axis PA.

Referring to FIG. 1B, gearbox 30 can receive rotational energy from lowspeed shaft 28 via an input coupling 33 and transmit rotational energyto fan 14 via fan shaft 34. Gearbox 30 can include an epicyclical gearsystem, such as a star gear system or a planet gear system. As shown,gearbox includes a planet gear system including a sun gear 42 meshedwith a plurality of planet gears 44, which are each meshed with a ringgear 46. A carrier 48 can include a plurality of posts (not labeled).Each post can extend through a central aperture (not labeled) of oneplanet gear 44.

During operation, low speed spool 28 can rotationally drive sun gear 42.By virtue of being meshed between sun gear 42 and ring gear 46, planetgears 44 can orbit about sun gear 42 and each planet gear 44 can rotateabout its central axis. Since carrier posts (not labeled) extend throughplanet gears 44, the orbital motion of planet gears 44 can cause carrier48 to rotate about its central axis. Carrier 48 can be splined to fanshaft 34, from which fan blades 36 can radially extend.

Although not shown, a star gear system can share the same basiccomponents as the planetary gear system of FIG. 1B. Therefore, theoperation of a star gear system can be explained with reference to theelement numbers in FIG. 1B. In a star gear system, each planet gear 44(i.e., star gear) can be rotate in-place about a carrier post 48.Carrier 48 can be static. Ring gear 46 can be rotatable. Duringoperation, rotation of sun gear 42 can cause each star gear 44 to rotateabout a respective static carrier post 48. The rotation of star gears 44can drive ring gear 46, which can be splined to fan shaft 34.

Referring to FIG. 1B, first and second bearing assemblies 52, 54 canradially support fan shaft 34. Third bearing assembly 56 can radiallysupport low speed shaft 28. Gas turbine engine 10 can include many otherbearing assemblies for radially supporting low speed shaft 28 at otherlocations and for radially supporting high speed shaft 26.

In FIG. 1B, first and second bearing assemblies 52, 54 can be rollerbearing assemblies, with a plurality of bearings (not labeled) disposedbetween an inner race (not labeled) of fan shaft 34 and an outer race(not labeled) of first core static support structure 62. Third bearingassembly 56 can be a roller bearing assembly with a plurality ofbearings (not labeled) disposed between an inner race (not labeled) oflow speed shaft 28 and an outer race (not labeled) of second core staticsupport structure 64.

FIG. 3 illustrates an embodiment of a first cooling architecture 300(also called a system, a rotational assembly, etc.), which can includean inner component (“IC”) 320, an outer component (“OC”) 340, and abearing assembly 360 configured to rotatably support IC 320 with respectto OC 340. Both IC 320 and OC 340 can be rotatable about central axisCA, which can be collinear with principle axis PA. For example, IC 320can be low speed shaft 28 and OC 340 can be high speed shaft 26.Alternatively, only one of IC 320 and OC 340 can be rotatable aboutcentral axis CA, which can be collinear with principle axis PA. Forexample, IC 320 can be a shaft and OC 340 can be outer support structureor OC 340 can be a shaft and IC 320 can be inner support structure.

According to some embodiments, central axis CA can be offset from, butparallel to, principle axis PA. For example, IC 320 can be a carrierpost, OC 340 can be a planet or star gear, and CA can be the centralaxis of the carrier post. According to some embodiments, first coolingarchitecture 300 is employed in a non-gas turbine engine setting. Putdifferently, the claimed inventions can be applied to a geared turbofan(FIGS. 1A and 1B) or a gas turbine electric generator system (FIG. 2),but can be used in other contexts as well. The claimed inventions arenot limited to any particular context unless otherwise explicit.

Referring to FIGS. 3 and 4, IC 320 can include a longitudinallyextending inner base 322 and an inner race 324. Inner base 322 can behollow or solid. Inner race 324 can be a collar disposed about (e.g.,press-fitted about) a small longitudinal segment of inner section 322.Inner race 324 can be a groove defined in inner section 322. Inner race324 can include (e.g., define) a longitudinally extendingcircumferential inner passage 326 for accommodating an inner workingfluid 328. Inner race 324 can include an inner running surface 324 aconfigured to contact bearings 362 and an inner mounting surface 324 bsecured to inner base 322.

Similarly, OC 340 can include a longitudinally extending outer base 342and an outer race 344. Outer base 342 can have annular cross-section, asshown in FIGS. 3 and 4. Alternatively, the view of outer base 342 inFIGS. 3 and 4 can be fragmentary and the cross-section of outer base 342can be any geometrical shape. Outer race 344 can be a collar disposedwithin (e.g., press-fitted within) a small longitudinal segment of outersection 342. Outer race 344 can be a groove defined in outer section342. Outer race 344 can include (e.g., define) a longitudinallyextending circumferential outer passage 346 for accommodating an outerworking fluid 348. Outer race 344 can include an outer running surface344 a configured to contact bearings 362 and an outer mounting surface344 b secured to outer base 342. Inner working fluid 328 and outerworking fluid 348 can be the same or different fluid.

Bearing assembly 360 can be representative of any bearing assembly ingas turbine engine 10, including first, second, and third bearingassemblies 52, 54, 56. Bearing assembly 360 can include a plurality ofroller bearings 362. A cage 364 can maintain a fixed circumferentialspacing relationship between roller bearings 362. Roller bearings 362can have many different geometries such as spherical, cylindrical,cylindrical-tapered, and needle geometries. Cage 364 is omitted invarious Figures, including FIG. 4.

During operation, one or both of IC 320 and OC 340 can rotate aboutcentral axis CA. IC 320 can contact (i.e., be configured to contact)bearings 362 via inner race 324 at inner contact regions 330. OC 340 cancontact (i.e., be configured to contact) bearings 362 via outer race 344at outer contact regions 350. Bearings 362 can maintain constant radialspacing between IC 320 and OC 340. Bearings 362, inner race 324, andouter race 344 can be configured to minimize friction generated at innercontact regions 330 and outer contact regions 350.

Each bearing 362 can be rotatable about a respective bearing centralaxis BCA within cage 320. Bearings 310 may rotate about bearing centralaxes BCA in response to torque transferred from IC 320 and/or OC 340.Cage 364 can be floating (i.e., rotationally independent of both IC 320and OC 340). Thus, bearings 362 may orbit central axis CA while rotatingabout their respective bearing central axes BCA. Alternatively, cage 320can be fixed to one of IC 320 and OC 340.

Over time, the friction generated at inner contact regions 330 and/orouter contact regions 350 can produce destructive amounts of heat,especially at rotational speeds present in a gas turbine engine 10.Various fluids can be supplied to first cooling architecture to (a)lubricate bearings 362 and races 324, 344 and/or (b) cool bearings 362and races 324, 344. According to various embodiments, first coolingarchitecture 300 supplies one or more of (e.g., all of): inner workingfluid 328 for directly cooling inner race 324, outer working fluid 348for directly cooling outer race 344, and intermediate working fluid 378for directly cooling and lubricating inner race 324, outer race 344, andbearings 362.

Referring to FIG. 4, an inner inlet 332 can supply cooled inner workingfluid 328 to inner passage 326. An inner outlet 334 can withdraw heatedinner working fluid 328 from inner passage 326. Inner inlet 332, innerpassage 326, and inner outlet 334 can define at least a portion of aninner cooling cycle 420. Similarly, an outer inlet 352 can supply cooledouter working fluid 348 to outer passage 346. An outer outlet 354 canwithdraw heated outer working fluid 348 from outer passage 346. Outerinlet 352, outer passage 346, and outer outlet 354 can define at least aportion of an outer cooling cycle 440.

Inlets 332, 352 and outlets 334, 354 can be one or more tubes extendingthrough bores (not labeled) in IC 320 and OC 340. As shown in FIG. 5, aplurality of inlets 332, 352 can be installed at periodiccircumferential intervals. Although not shown, outlets 334, 354 can havethe same arrangement (although at a different longitudinal position). Aspreviously discussed, inner base 322 of IC 320 can be hollow. Whenhollow, inner base 322 can carry inner working fluid to and/or frominner passage 326. For example, one or more tubes can extend throughinner base 322 to the one or more inlets 332 and one or more tubes canextend through inner base 322 to the one or more outlets 334.

According to some embodiments, inner and/or outer baffles 392, 394 canbe installed within fluid chambers 326, 328 to direct fluid flow (seeFIG. 4). When installed, baffles 392, 394 can have a helical shape toforce inner and outer fluid 328, 348 to flow in a helical path betweeninlet 332, 352 and outlet 334, 354.

Similar to outer inlets 352, one or more intermediate inlets 372 (e.g.,nozzles) can radially extend through OC 340. Each intermediate inlet 372can extend through a complete radial thickness of OC 340 to spray cooledintermediate fluid 378 in the circumferential volume 374 defined betweenIC 320 and OC 340. Although not shown, one or more intermediate outletscan be provided to withdraw heated intermediate fluid 378 fromcircumferential volume 374. Intermediate inlet 372, circumferentialvolume 374, and intermediate outlets (not shown) can define at least aportion of an intermediate cooling cycle 460.

Inner working fluid 328 and outer working fluid 348 can be the samefluid such as air, water, synthetic refrigerant, or oil. Intermediateworking fluid 378 can be a lubricant such as oil. Inner working fluid328, outer working fluid 348, and intermediate working fluid 378 caneach originate from the same source (e.g., reservoir or pump). Thus,inner cooling cycle 420, outer cooling cycle 440, and intermediatecooling cycle 460 can merge. Alternatively, inner working fluid 328,outer working fluid 348, and intermediate working fluid 378 can each beseparately maintained and thus inner cooling cycle 420, outer coolingcycle 440, and intermediate cooling cycle 460 can each be fluidlydistinct. According to some embodiments, inner cooling cycle 420 andouter cooling cycle 440 merge (and thus are in fluid communication)while intermediate cooling cycle 460 is fluidly distinct.

As shown in FIG. 4, chambers 326, 346 can extend beyond bothlongitudinal ends of bearing 362. Chambers 326, 346 can be completelydefined within races 324, 344 such that no working fluid 328, 348disposed within chambers 326, 346 contacts bases 322, 342. Chambers 326,346 can be defined within races 324, 344 such that at least a portion(and in some embodiments, all) of working fluid 328, 348 therein isradially closer to bearing race running surfaces 324 a, 344 a thanbearing race mounting surfaces 324 b, 344 b.

Referring to FIGS. 6A and 6B, one or both of inner race 324 and outerrace 344 can define running channels 602, 604 for longitudinallyretaining bearings 362. In these embodiments, one or both of innerchamber 326 and outer chamber 346 can have a U-shaped cross section toradially extend into the opposing rims defining running channels 602,604. As shown in FIG. 6A, the U-shaped cross section can be defined byadding a pair of radially extending channels 682, 684 to chambers 326,346. As shown in FIG. 6B, the U-shaped cross section can be defined byarcing chambers 326, 346 along the longitudinal direction such that thecross section of chambers 326, 346 is annular.

FIG. 7 illustrates an embodiment of a two-phase pump-loop system 700forming both inner cooling cycle 420 and outer cooling cycle 440.Two-phase pump-loop system 700 can be controlled with a processingsystem (“PS”) 20, which is further discussed below. PS 20 can controlpump-loop system 700 to maintain one or more desired temperatureprofiles (e.g., to keep one or more temperatures of bearing assembly 300below predetermined values).

The present disclosure refers to PS 20 controlling various fluid cyclesto achieve certain fluid states (e.g., a saturated liquid state, asaturated vapor state). According to some embodiments, PS 20 exerciseseach of the disclosed controls based on temperature and/or pressuremeasurements of working fluid at the controlled location. For example,when the present disclosure states that PS 20 can control condenser 740such that working fluid is in a saturated liquid state, such adisclosure should be understood to convey that a temperature and/orpressure sensor can be disposed at the outlet of the condenser 740 andPS 20 can control condenser 740 based on measurements from thosesensor(s).

Referring to FIG. 7, PS 20 can control pump 710 to pressurize workingfluid 328, 348 from a saturated liquid to a sub-cooled or saturatedliquid. PS 20 can control one or more inner valves 720 to regulate flowof inner working fluid 328 into inner chamber 326 and one or more outervalves 730 can regulate flow of outer working fluid 348 into outerchamber 348. Inner valves 720 can be disposed fluidly upstream of innerinlets 332 and outer valves 730 can be disposed fluidly upstream ofouter inlets 352. If sub-cooled, PS 20 can be configured to modulatevalves 720, 730 to return working fluid 328, 348 into a saturated liquidstate.

Inner and outer working fluids 328, 348 can absorb heat from inner andouter races 324, 344 while in inner and outer chambers 326, 346. PS 20can control flow rate of inner and outer working fluids 328, 348 suchthat upon entering outlets 334, 354, inner and outer working fluids 328,348 are in a saturated vapor state. Inner and outer working fluids 328,348 can merge before being flowing through a condenser 740. PS 20 cancontrol flow rate, temperature, and/or pressure of a counter-fluidthrough condenser 740 (e.g., air, a separate refrigerant) such thatworking fluid 328, 348 departing condenser 740 is in a saturated liquidstate.

FIG. 8 illustrates an embodiment of a vapor-compression system 800forming both inner cooling cycle 420 and outer cooling cycle 440. PS 20can control vapor-compression system 800 to maintain one or more desiredtemperature profiles (e.g., to keep one or more temperatures of bearingassembly 300 below predetermined values).

Referring to FIG. 8, PS 20 can control compressor 810 to pressurizeworking fluid 328, 348 from a saturated vapor to a super-heated vapor.PS 20 can control condenser 820 to cool working fluid into a saturatedliquid (e.g., by regulating flow, temperature, and/or pressure of acounter-fluid as discussed above). PS 20 can control one or more innerexpansion valves 830 to depressurize inner working fluid 328 from asaturated liquid to a liquid/vapor mixture. PS 20 can control one ormore outer expansion valves 840 to depressurize outer working fluid 348from a saturated liquid to a liquid/vapor mixture. Expansion valves 830,840 can be directly fluidly upstream of inlets 332, 352.

Inner and outer working fluids 328, 348 can absorb heat from inner andouter races 324, 344 while in inner and outer chambers 326, 346. PS 20can control flow of inner and outer working fluids 328, 348 (e.g., bymodulating expansion valves 830, 840) such that upon entering outlets334, 354, inner and outer working fluids 328, 348 are in a saturatedvapor state.

According to some embodiments (not shown), inner and outer coolingcycles 420, 440 are fluidly independent two-phase pump-loop systems orfluidly independent vapor-compression systems. PS 20 can control eachindependent system in the manner discussed above.

FIG. 17 shows an embodiment of a method 1700 of controlling coolingsystems 700, 800 (see FIGS. 7 and 8). Method 1700 can cause intermediatecooling cycle 460 to supply an ideal amount of lubrication for bearingassembly 300 by relying on inner and outer cooling cycles 420, 440 toperform supplemental cooling. Such a control may be desirable when theflow rate of intermediate cooling cycle 460 for supplying ideallubrication to bearing assembly 300 is different than the flow rateneeded to supply ideal cooling to bearing assembly 300. In general,method 1700 can involve an iterative control process where a metric(e.g., flow rate) of intermediate cooling cycle 460 is adjusted upwardsand/or downwards to minimize the heat generation of bearing assembly300. Method 1700 can occur in parallel with any other methods disclosedherein.

At block 1702, PS 20 can determine that bearing assembly 300 has reacheda steady state condition (e.g., by determining that inlet and outlettemperatures of cooling cycles 420, 440, 460 have stabilized to onlyfluctuate within a predetermined upper and lower limit). At block 1704,PS 20 can determine (e.g., estimate) a total amount of heat generated bybearing assembly 300 per unit time. PS 20 can do so by determining(i.e., based on) a total amount of cooling performed by cycles 420, 440,460 on bearing assembly 300 at a steady state condition. PS 20 candetermine a total (i.e., aggregate) amount of cooling based on (a) aninlet temperature and/or pressure of each cooling cycle, (b) an outlettemperature and/or pressure of each cooling cycle, and (c) a flow rateof each cooling cycle. The total amount of heat generated per unit timecan be called a first heat generation rate.

At block 1706, PS 20 can increase a flow rate of intermediate cycle 460by a first amount (here, “amount” means magnitude). PS 20 can, inparallel, control inner and outer cycles 420, 440 in the manner(s)discussed above (e.g., the above-discussed two-phase pump or vaporcompression controls). At block 1708, PS 20 can re-perform blocks 1702and 1704 to find a second heat generation rate of bearing assembly 300.

If the second heat generation rate is less than the first heatgeneration rate, then PS 20 can re-perform block 1708 to find a thirdheat generation rate of bearing assembly 300, and so on, until an endcondition is met (e.g., a maximum flow rate of intermediate cycle 460has been reached) or until a subsequent heat generation rate exceeds aprevious heat generation rate. At block 1710, PS 20 can revert to theprevious intermediate cycle 460 flow rate (if the previous heatgeneration rate is less than the subsequent heat generation rate) ormaintain the subsequent intermediate cycle 460 flow rate (if theprevious heat generation rate is less than the subsequent heatgeneration rate).

At block 1712, PS 20 can re-perform blocks 1706, 1708, and 1710 exceptby decreasing the flow rate of intermediate cycle 460 by a secondamount. The second amount can be equal to the first amount if PS 20 onlyperformed block 1706 once when increasing the flow rate of intermediatecycle 460. Otherwise, the second amount can be less than the firstamount.

At block 1714, PS 20 can re-perform block 1712, except by increasing theflow rate of intermediate cycle 460 by a third amount, the third amountbeing less than the first amount. At block 1716, PS 20 can re-performblock 1712, except by decreasing the flow rate of intermediate cycle 460by a fourth amount, the fourth amount being less than the second amount.

PS 20 can continue looping through blocks 1714 and 1716 until detectinga new condition of gas turbine engine 10 at block 1718 (e.g., a newthrottle setting for gas turbine engine 10). At block 1718, PS 20 canselect initial conditions of cooling cycles 420, 440, 460 based on thenew engine condition (e.g., based on a lookup table). At block 1720, PS20 can control inner and outer cycles 420, 440 in the manner(s)discussed above (e.g., the above-discussed two-phase pump or vaporcompression controls) and return to block 1702.

FIG. 9 illustrates an embodiment of a second cooling architecture 900(also called a system, a rotational assembly, etc.). Second coolingarchitecture 900 can share components with first cooling architecture300. Any features in first cooling architecture 300 can apply to secondcooling architecture 900 and vice-versa. As a result, the same elementnumbers are used across first and second cooling architectures 300, 900.Potential points of departure between cooling architectures 300, 900 arediscussed below.

Referring to FIGS. 9 and 10, inner race 324 can include (e.g., define) aplurality of inner passages 902. Outer race 344 can include a pluralityof outer passages 904. Nine inner 902 and nine outer 904 passages areshown and appended with letters “a-i” depending on their longitudinalposition. Inner passages 902 can be configured to inject (i.e., pass)inner fluid 928 from inner chamber 926 into circumferential volume 374.Outer passages 904 can be configured to inject outer fluid 948 fromouter chamber 946 into circumferential volume 374.

Although not shown, intermediate cooling cycle 460 can be present. Insome embodiments however, intermediate cooling cycle 460 is absent suchthat inner and outer working fluid 928, 948 are the exclusive sourcecooling and lubrication for bearing assembly 360 (other than air).According to these embodiments inner and outer working fluid 928, 948can be oil or a refrigerant for a vapor-compression refrigeration cycle.

Referring to FIG. 11, refrigerant injected by passages 902, 904 can forma longitudinally extending circumferential inner cushion 912 at innercontact regions 330 and a longitudinally extending circumferential outercushion 914 at outer contact regions 350 to minimize (and in some cases,eliminate) friction between bearings 362 and inner race 324 and/orbearings 362 and outer race 344.

Refrigerant injected by passages 902, 904 (or portions thereof) that arecircumferentially and/or longitudinally distant from bearings 362 alongwith refrigerant injected by passages 902, 904 that are co-radial andco-circumferential with bearings 362 can cool bearing assembly 360. Tofurther discourage longitudinal movement of bearings 362, inlets 332,352 can be disposed at the longitudinal centers of chambers 326, 346 asshown in FIG. 11 to equalize pressure differential (if any) between thelongitudinal ends of chambers 326, 346.

Referring to FIG. 11, refrigerant injected by passages 902, 904 (orportions thereof) that are circumferentially aligned, but longitudinallydistant from bearings 362 can form pressure clouds 920 thatlongitudinally retain bearings 362. In FIG. 11, the depicted portions ofpassages 902 a, 902 b, 902 h, 902 i, 904 a, 904 b, 904 h, and 904 i arecircumferentially aligned, but longitudinally distant from bearing 362.As shown in FIG. 12, opposing longitudinal end passages (e.g., 902 a,902 i; 902 b, 902 h; 904 a, 904 i; 904 b, 904 h) can be slanted withrespect to the radial direction to enhance the retaining effect ofpressure clouds 920. Longitudinally central passages (e.g., passages 902c, 902 d, 902 e, 902 f, 902 g, 904 c, 904 d, 904 e, 904 f, 904 g) canremain radially aligned. Therefore, the radial alignment of passages902, 904 can fluctuate across the longitudinal direction.

FIG. 13 illustrates an embodiment of a vapor-compression system 1300forming both inner cooling cycle 420 and outer cooling cycle 440. PS 20can control vapor-compression system 1300. PS 20 can controlvapor-compression system 1300 to maintain one or more desiredtemperature profiles (e.g., to keep one or more temperatures of bearingassembly 300 below predetermined values).

Referring to FIG. 13, PS 20 can control compressor 1310 to pressurizeworking fluid 328, 348 from a saturated vapor to a super-heated vapor.PS 20 can control condenser 1320 (e.g., by regulating counter-fluid asdiscussed above) to cool working fluid 328, 348 into a saturated liquid.Working fluid 328, 348 can flow through inlets 332, 352 into annularchambers 326, 346.

PS 20 can control vapor-compression system 1300 such that working fluid328, 348 within chambers 326, 346 is in a saturated liquid state.Working fluid 328, 348 can depart chambers 326, 346 via passages 902,904. Immediately upon exiting passages 902, 904 and enteringcircumferential volume 374, working fluid 328, 348 can expand into aliquid-vapor mixture. Simultaneously, working fluid 328, 348 can absorbheat from bearing assembly 360. Although not shown, one or more passages(e.g., tubes, conduits, etc.) can be disposed in circumferential volume374 for scavenging working fluid 328, 348. Due to heat absorption,working fluid 328, 348 can reach the scavenging passages in a saturatedvapor or superheated vapor state. From there, working fluid 328, 348 canreturn to compressor 1310.

According to some embodiments, flow control valves 1330, 1340 (e.g.,expansion valves) can be disposed between condenser 1320 and chambers326, 346. According to these embodiments, PS 20 can control condenser1320 to subcool working fluid 328, 348 and flow control valves 1330,1340 to expand subcooled liquid working fluid 328, 348 into a saturatedliquid state.

FIG. 14 illustrates an embodiment of a vapor-compression system 1400forming both inner cooling cycle 420 and outer cooling cycle 440. PS 20can control vapor-compression system 1400. PS 20 can controlvapor-compression system 1400 to maintain one or more desiredtemperature profiles (e.g., to keep one or more temperatures of bearingassembly 300 below predetermined values).

Referring to FIG. 14, a pair of compressors 1310 a, 1310 b and a pair ofcondensers 1320 a, 1320 b can exist in parallel. Working fluid 328, 348can mix in circumferential volume 374. Afterwards, passage 1402 canscavenge the mixed working fluid for compressor 1310 a and passage 1404can scavenge the mixed working fluid for compressor 1310 b. PS 20 canindependently control each compressor 1310 a, 1310 b such that workingfluid 328, 348 enters chambers 326, 346 in a saturated liquid state.

Referring to FIG. 15, one or more passages 902, 904 can be radiallytapered to expand working fluid 328, 348 prior to working fluid 328, 348reaching circumferential volume 374. According to some embodiments,passages 902, 904 in the longitudinally central area (e.g., passages 902d, 902 e, 902 f, 904 d, 904 e, 904 f), which produce cushions 912, 914,are tapered to a greater extent than longitudinal end passages (e.g.,passages 902 a, 902 b, 902 c, 902 g, 902 h, 902 i, 904 a, 904 b, 904 c,904 g, 904 h, 904 i). The extent of tapering can be defined by the ratioof passage inlet area to passage outlet area. Therefore, the extent ofpassage tapering can longitudinally fluctuate. As shown, each taperedpassage can have a larger outlet area than inlet area.

As previously discussed with reference to FIG. 5, cooling architectures300, 900 can include a plurality of co-circumferential inner inlets 332,a plurality of co-circumferential outer inlets 352, a plurality ofco-circumferential inner outlets 334, and a plurality ofco-circumferential outer outlets 354. According to some embodiments,each inlet 332, 352 can include an independent flow control valve. PS 20can be configured to control each valve to non-uniformly distributefresh working fluid 328, 348 into chambers 326, 346. For example, andreferring to FIG. 5, based on detecting a higher temperature at region502, PS 20 can close (i.e., at least partially close) inlets 332 a, 332b, and 332 c and PS 20 can open (e.g., increase the opening of) inlet332 d. Put differently, PS 20 can control the opening degrees of inlets332, 352 based on one or more determined (e.g., estimated) temperaturesof bearing assembly 300.

Gas turbine engine 10 and/or electric generator 200 can include aprocessing system (“PS”) 20. Referring to FIG. 16, PS 20 can include oneor more processors 1001, memory 1002, one or more input/output devices1003, one or more sensors 1004, one or more user interfaces 1005, andone or more actuators 1006.

Processors 1001 can include one or more distinct processors, each havingone or more cores. Each of the distinct processors can have the same ordifferent structure. Processors 1001 can include one or more centralprocessing units (CPUs), one or more graphics processing units (GPUs),circuitry (e.g., application specific integrated circuits (ASICs)),digital signal processors (DSPs), and the like. Processors 1001 can bemounted on a common substrate or to different substrates.

Processors 1001 are configured to perform a certain function, method, oroperation at least when one of the one or more of the distinctprocessors is capable of executing code, stored on memory 1002 embodyingthe function, method, or operation. Processors 1001 can be configured toperform any and all functions, methods, and operations disclosed herein.

For example, when the present disclosure states that PS 20 performs/canperform task “X”, such a statement should be understood to disclose thatPS 20 can be configured to perform task “X”. Mobile device 100 and PS 20are configured to perform a function, method, or operation at least whenprocessors 1001 are configured to do the same.

Memory 1002 can include volatile memory, non-volatile memory, and anyother medium capable of storing data. Each of the volatile memory,non-volatile memory, and any other type of memory can include multipledifferent memory devices, located at multiple distinct locations andeach having a different structure.

Examples of memory 1002 include a non-transitory computer-readable mediasuch as RAM, ROM, flash memory, EEPROM, any kind of optical storage disksuch as a DVD, a Blu-Ray® disc, magnetic storage, holographic storage,an HDD, an SSD, any medium that can be used to store program code in theform of instructions or data structures, and the like. Any and all ofthe methods, functions, and operations described in the presentapplication can be fully embodied in the form of tangible and/ornon-transitory machine-readable code saved in memory 1002.

Input-output devices 1003 can include any component for trafficking datasuch as ports, antennas (i.e., transceivers), printed conductive paths,and the like. Input-output devices 1003 can enable wired communicationvia USB®, DisplayPort®, HDMI®, Ethernet, and the like. Input-outputdevices 1003 can enable electronic, optical, magnetic, and holographic,communication with suitable memory 1003. Input-output devices 1003 canenable wireless communication via WiFi®, Bluetooth®, cellular (e.g.,LTE®, CDMA®, GSM®, WiMax®, NFC®), GPS, and the like. Input-outputdevices 1003 can include wired and/or wireless communication pathways.

Sensors 1004 can capture physical measurements of environment and reportthe same to processors 1001. Examples of sensors 1004 include pressuresensors, temperature sensors, and flow rate sensors, which can bedisposed at any (e.g., every) point in the cooling circuit diagrams.User interface 1005 can include display 120 (e.g., LED touchscreens(e.g., OLED touchscreens), physical buttons, speakers, microphones,keyboards, and the like. Actuators 1006 can enable processors 1001 tocontrol mechanical forces. For example, actuators can be electronicallycontrollable motors disposed in pumps, valves, and compressors. Everyvalve, pump, and compressor discussed herein can be independentlycontrollable by PS 20 based on pressure and/or temperature measurements.

PS 20 can be distributed. For example, some elements of PS 20 can bedisposed inside an aircraft body while other elements of PS 20 can bedisposed in gas turbine engine 10. PS 20 can have a modular design wherecertain features have a plurality of the aspects shown in FIG. 16. Forexample, I/O modules can include volatile memory and one or moreprocessors.

We claim:
 1. A rolling bearing system comprising: a rotatable shaft defining an axis; a support member positioned radially outward of said shaft; an annular inner race coupled to said shaft; an annular outer race coupled to said support member and axially aligned with said annular inner race; and a bearing assembly comprising a plurality of roller bearings circumferentially spaced and radially disposed between said annular inner race and said annular outer race, wherein at least one of said annular inner race and said annular outer race defines an interior chamber bound at least in part by a circumferential bearing facing wall, said bearing facing wall defining a plurality of outlet passages providing fluid communication between the interior chamber and an exterior of the annular inner race or an exterior of the annular outer race, wherein one or more of the plurality of outlet passages are radially angled and/or radially tapered.
 2. The rolling bearing system of claim 1 wherein said annular inner race defines an interior chamber bound at least in part by the circumferential bearing facing wall, said bearing facing wall defining the plurality of outlet passages providing fluid communication between the interior chamber and the exterior of the annular inner race.
 3. The rolling bearing system of claim 2 wherein the interior chamber is a first interior chamber, said annular outer race defines a second interior chamber bound at least in part by the circumferential bearing facing wall, said bearing facing wall defining the plurality of outlet passages providing fluid communication between the second interior chamber and the exterior of the annular outer race.
 4. The rolling bearing system of claim 1 wherein said annular outer race defines the interior chamber bound at least in part by the circumferential bearing facing wall, said bearing facing wall defining the plurality of outlet passages providing fluid communication between the interior chamber and the exterior of the annular outer race.
 5. The rolling bearing system of claim 1 wherein said plurality of outlet passages are spaced axially along said bearing facing wall.
 6. The rolling bearing system of claim 5 wherein said plurality of outlet passages are spaced circumferentially around said bearing facing wall.
 7. The rolling bearing system of claim 1 wherein said plurality of outlet passages are spaced circumferentially around said bearing facing wall.
 8. The rolling bearing system of claim 7 wherein one or more of said plurality of outlet passages are circumferentially aligned with each roller bearing.
 9. The rolling bearing system of claim 1 wherein said support member comprises a rotatable shaft.
 10. A rolling bearing system comprising: a rotatable member defining an axis; a support member disposed radially outward from said rotatable member; an annular inner race coupled to a shaft, said annular inner race defining an interior chamber, one or more inlet passages, and a plurality of outlet passages spaced circumferentially around a bearing facing wall; an annular outer race coupled to said support member and axially aligned with said annular inner race, said annular outer race defining an interior chamber, one or more inlet passages, and a plurality of outlet passages spaced circumferentially around a bearing facing wall; a bearing assembly comprising a plurality of roller bearings circumferentially spaced and radially disposed between said annular inner race and said annular outer race, each of said roller bearings being circumferentially aligned with one or more of said outlet passages circumferentially spaced around the bearing facing wall of said annular inner race and the bearing facing wall of said annular outer race; and a heat management system comprising: a cooling fluid flowpath including in part one or more of the inlet passages defined by the annular inner race, the interior chamber defined by the annular inner race, and the plurality of outlet passages defined by said annular inner race; and a cooling fluid flowpath including in part one or more of the inlet passages defined by the annular outer race, the interior chamber defined by the annular outer race, and the plurality of outlet passages defined by said annular outer race, wherein the heat management system includes a cooling fluid, the cooling fluid comprising a vapor phase.
 11. The rolling bearing system of claim 10 wherein the cooling fluid of said heat management system comprises lube oil.
 12. The rolling bearing system of claim 10 wherein said heat management system includes a cooling fluid sufficiently pressurized to form a fluidic barrier between the bearing facing wall of said annular inner race and said roller bearings and between the bearing facing wall of said annular outer race and said roller bearings.
 13. In a roller bearing system comprising a plurality of roller bearings disposed circumferentially around and radially between an annular inner race and an annular outer annular race, each defining an interior chamber, a method of heat management comprising: flowing a cooling fluid into each of the interior chambers defined by the annular inner race or the annular outer race, respectively; and ejecting the cooling fluid from the interior chambers through a plurality of outlet passages, at least one of the plurality of outlet passages at a circumferential location aligned with a respective one of the roller bearings, wherein one or more of the plurality of outlet passages are radially angled and/or radially tapered.
 14. The heat management method of claim 13 wherein the cooling fluid is lube oil.
 15. The heat management method of claim 13 wherein the cooling fluid comprises a vapor phase.
 16. The heat management method of claim 15 comprising a two-phase pump loop.
 17. The heat management method of claim 13 comprising pressurizing the cooling fluid to effect a formation of a fluidic barrier between the annular inner race and the roller bearings and between the annular outer race and the roller bearings. 